Removing iam_roles from multiple modules

This commits removes the iam_roles variables from the modules:
 - artifact-registry
 - bigtable-instance
 - cloud-function
 - container-registry
 - endopoints
 - pubsub
 - source-repository

modules/pubsub/variables.tf

@@ -41,16 +41,10 @@ variable "defaults" {
 
 variable "iam_members" {
   description = "IAM members for each topic role."
-  type        = map(list(string))
+  type        = map(set(string))
   default     = {}
 }
 
-variable "iam_roles" {
-  description = "IAM roles for topic."
-  type        = list(string)
-  default     = []
-}
-
 variable "kms_key" {
   description = "KMS customer managed encryption key."
   type        = string
@@ -109,12 +103,6 @@ variable "subscriptions" {
 
 variable "subscription_iam_members" {
   description = "IAM members for each subscription and role."
-  type        = map(map(list(string)))
-  default     = {}
-}
-
-variable "subscription_iam_roles" {
-  description = "IAM roles for each subscription."
-  type        = map(list(string))
+  type        = map(map(set(string)))
   default     = {}
 }